The second is of Esau and Jacob, who when yet in their mother’s womb, and had done neither good nor evil, it was said: “the older shall serve the younger:” [and] “Jacob have I loved, but Esau have I hated.” Therefore it is plain, that they which are of faith, are the children of Abraham.
But some will object (as the Jews do, and certain cavillers at this day) saying, that this word faith in the Hebrew signifieth truth, and therefore we do not rightly apply it. And because of the simple and ignorant, we will briefly answer their cavillations.
Faith is nothing else but the truth of the heart; that is to say, a true and right opinion of the heart as touching
God. Now, faith only thinketh and judgeth rightly of God, and not reason. And a man doth think rightly of God, when he believeth His Word. And when he will measure God without the Word, and believe Him according to his wisdom of reason, he hath no right opinion of God in his heart, and therefore he cannot think or judge of Him as he should do. ..
Truth therefore is faith itself, which judgeth rightly of God, namely that God regardeth not our works and
righteousness, because we are unclean: but that He will have mercy upon us, if we believe in His Son, whom
He hath sent to be a sacifice [propitiation, hilasmos] for the sins of the whole world (1 John 2:2). This is a true opinion of God, and in very deed nothing else but faith itself.
Martin Luther, Kregel, Galatians 3:7, Romans 9, p. 135f.
